Network resources such as data files, web pages, and collaboration tools may be provided on a computer network so that multiple users can access the resources through the network. Typically, the network resources are provided at a network location through a server computer that can be accessed by the client computers of users. These users may post a network resource at the network location for access by the other users. However, such sharing of network resources often calls for security measures to prevent unauthorized access to the network resources.
To prevent unauthorized access, network locations such as sites on the world wide web utilize authentication and authorization techniques when users attempt to access the network resource. Authentication techniques may be of various forms, such as requiring entry of a user name and password for each network site containing a network resource. To improve the practicality of authentication, a centralized authentication service such as .NET™ Passport™ may be used to require the user to log in with a user name and password once at the authentication ID server to obtain one or more computer cookies with an authentication ID. The authentication ID of the cookie is then checked at various network locations when the user attempts to access network resources rather than requiring the user to again enter a user name and password to be authenticated.
Once the user has been authenticated, the authenticated identity of the user is then compared to an access list to determine whether the user has authorization to access a particular network resource. Thus, the access list has permissions associated with the authentication ID of each user who has been given some authorization. When the access list gives authorization to the user for a network resource, the user is then given access to the resource. If the access list does not provide authorization for a network resource to a user, that user is denied access to the resource.
One user who has access to a network resource, such as one who posted the resource to the network, may wish to share the resource with a guest user. Access to this resource may require authentication by obtaining an authentication ID from the authentication ID server. However, the user wishing to share the resource may not know whether the guest user has an account with the authentication ID server. If the guest user does not have an account, then access cannot be granted to the network resource for this guest user. Furthermore, the user wishing to share the network resource cannot proceed to set up authorization for the guest user in the access list since the guest user does not have an authentication ID account that can be referenced in the access list.